U.S. patent application number 16/616662 was filed with the patent office on 2021-05-13 for assembly for detecting operating parameters within an oven cavity.
The applicant listed for this patent is ELECTROLUX APPLIANCES AKTIEBOLAG. Invention is credited to Arnd HOFMANN, Klaus SCHLOTTERER-FRATOIANNI.
Application Number | 20210140647 16/616662 |
Document ID | / |
Family ID | 1000005369809 |
Filed Date | 2021-05-13 |
![](/patent/app/20210140647/US20210140647A1-20210513\US20210140647A1-2021051)
United States Patent
Application |
20210140647 |
Kind Code |
A1 |
SCHLOTTERER-FRATOIANNI; Klaus ;
et al. |
May 13, 2021 |
ASSEMBLY FOR DETECTING OPERATING PARAMETERS WITHIN AN OVEN
CAVITY
Abstract
An assembly (10) for detecting operating parameters within an
oven cavity (22) comprises: *(a) a housing (12); *(b) a sensor (14,
64) disposed within the housing (12); *(c) an air inlet (16) for
feeding air into the housing (12); and *(d) an air outlet (18, 38)
through which air can leave the housing (12).
Inventors: |
SCHLOTTERER-FRATOIANNI; Klaus;
(Rothenberg ob der Tauber, DE) ; HOFMANN; Arnd;
(Rothenberg ob der Tauber, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ELECTROLUX APPLIANCES AKTIEBOLAG |
Stockholm |
|
SE |
|
|
Family ID: |
1000005369809 |
Appl. No.: |
16/616662 |
Filed: |
May 15, 2018 |
PCT Filed: |
May 15, 2018 |
PCT NO: |
PCT/EP2018/062635 |
371 Date: |
November 25, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24C 15/2007 20130101;
A21B 3/04 20130101; F24C 7/085 20130101 |
International
Class: |
F24C 7/08 20060101
F24C007/08; F24C 15/20 20060101 F24C015/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 7, 2017 |
EP |
17174764.5 |
Claims
1. Assembly for detecting operating parameters within an oven
cavity, the assembly comprising: (a) a housing; (b) a sensor
arranged within the housing; (c) an air inlet for feeding air into
the housing; and (d) an air outlet through which air can leave the
housing.
2. The assembly of claim 1, further comprising: a heatsink disposed
within the housing in contact with the sensor.
3. The assembly of claim 2, further comprising: a thermal interface
material disposed between the heatsink and the sensor.
4. The assembly of claim 1, wherein the sensor comprises at least
one of an optical sensor, an imaging system, a humidity sensor, a
temperature sensor, a gas sensor, a sound sensor, and a chemical
sensor.
5. The assembly of claim 1, further comprising a cover which covers
a receptive region of the sensor but which is permeable for a
physical or chemical parameter to be detected by the sensor.
6. The assembly of claim 5, wherein the sensor is a humidity sensor
and the cover comprises a membrane which is permeable for water
vapor.
7. The assembly of claim 5, wherein the sensor is an optical sensor
and the cover comprises a transparent element.
8. The assembly of claim 7, wherein the transparent element is
designed as an optical filter and/or lens.
9. The assembly of claim 1, wherein the housing or parts thereof
are made from a material having a thermal conductivity at standard
conditions of less than 10 W/mK.
10. The assembly of claim 1, further comprising a housing support
(52) for mounting the housing to a wall of the oven cavity.
11. The assembly of claim 10, wherein the housing support is made
of a material having a lower thermal conductivity than the
housing.
12. Oven with an oven cavity and the assembly of claim 1, the oven
comprising means for generating a forced air flow which is directed
to the air inlet, and wherein the assembly is located within the
oven cavity.
13. Oven with an oven cavity and the assembly of claim 1, wherein
the assembly is mounted to an exterior side of a wall of the oven
cavity and communicates with an interior of the oven cavity through
a region provided with the wall of the oven cavity which is
permeable for a physical or chemical parameter to be detected by
the sensor.
14. Oven of claim 12, wherein the housing is formed in part by a
deep drawn region in a wall of the oven cavity.
15. Oven of claim 12, wherein the air outlet is located to expel
air into the oven cavity.
16. Oven of claim 15, having an assembly as defined in claim 5,
wherein the air outlet comprises one or more outlet openings
located in a perimeter of the cover.
17. Oven of claim 12, wherein the air outlet is connected to a
conduit to remove air from the assembly.
18. Oven of claim 12, wherein the air outlet is located in a wall
of the housing so as to expel air to an exterior side of the
housing.
19. Oven of claim 12, wherein said means for generating a forced
air flow comprise a fan for feeding ambient air to the air inlet
16.
20. Oven of claim 12, further comprising an insulation layer at a
wall of the housing facing towards the oven cavity.
21. An oven comprising an oven cavity for cooking food therein, and
a sensor assembly, the sensor assembly being attached to or formed
in part with a wall of the oven cavity and comprising a sensor
housing and a sensor disposed within the sensor housing, said
sensor being adapted to detect an operating parameter during a
cooking operation within the oven cavity, at least a portion of
said sensor housing and/or said oven cavity between said sensor and
an interior of said cavity being transparent or permeable to the
operating parameter to be detected by the sensor, said sensor
housing further comprising an air inlet and an air outlet, means to
generate a forced flow of air into said inlet and over said sensor
so as to cool said sensor prior to being expelled from the sensor
housing via said air outlet, the air outlet configured to discharge
said flow of air in turbulent flow, said sensor housing being made
of a material having a thermal conductivity less than 1 W/m-K at
standard conditions of temperature and pressure, a heatsink in
thermal communication with said sensor within the sensor housing
and being effective to enhance thermal energy transfer from said
sensor into said stream of cooling air passed through said sensor
housing, and a layer of insulation at a wall of said housing facing
toward the oven cavity.
Description
[0001] The present invention relates to an assembly for detecting
operating parameters within an oven cavity.
[0002] Modern cooking ovens often are equipped with sensors to
detect operating parameters within the oven cavity, such as
temperature and/or humidity within the oven cavity. The oven also
may be equipped with optical sensors, such as an imaging system, to
automatically detect or monitor the load within the oven cavity, so
as to control operating parameters of the oven in dependency of the
load detected or of the cooking progress, such as a degree of
change in size or color of the food items being processed.
[0003] Evidently, in order to be able to detect the parameter or
parameters to be monitored, the sensors have to be placed at a
location that allows picking up the signals that are representative
of the parameter to be monitored, which necessitates that the one
or more sensors have to be arranged in close proximity to the oven
cavity. In case that the sensor is an optical sensor, the sensor
has to be located in eye-sight of the oven cavity. Due to the harsh
conditions prevailing in an oven, such as high temperature and high
humidity, it was suggested in the prior art to locate the sensor in
a chamber that is separate from the oven cavity, such as within an
air channel that is used to vent air from within the oven cavity to
the exterior. A problem with such systems, as they were suggested
for example in DE10 2004 210 673 A1, DE10 2004 056 839 A1 or DE 10
2006 058 617 B3, is that the sensor necessarily has to be
positioned remote from the oven cavity, which for an optical sensor
is disadvantageous due to the limited field of view. Furthermore,
when the sensor is located within a vent channel, so as to be
cooled by air that is removed from within the oven cavity, not only
does the positioning of the sensor within the vent channel
interfere with, and thus deteriorate, the venting action, but also
is the sensor cooling rather limited, given that the air that
leaves the oven cavity is of high temperature.
[0004] It is an object of the present invention to provide for an
assembly for detecting operating parameters within an oven cavity
which reliably allows monitoring the respective operating parameter
to be monitored, but which at the same time is effectively
protected against the harsh environment that may prevail within the
oven cavity during a cooking process.
[0005] In accordance with the present invention the above object is
solved by an assembly for detecting operating parameters within an
oven cavity, which assembly comprises a housing, a sensor disposed
within the housing, an air inlet for feeding air into the housing,
and an air outlet through which air can leave the housing.
[0006] Instead of providing for a sensor that is to be located in a
region of the oven, where there are less harsh operating conditions
as compared to those prevailing within the oven cavity, as it was
suggested in the prior art, the present invention provides for a
sensor assembly in which the sensor has its own cooling system, by
arranging the sensor within a housing through which air can be fed.
In this manner it is made possible to arrange temperature-sensitive
sensor systems, such as imaging systems or humidity sensors, in
direct ambience of an oven cavity.
[0007] In this manner, more direct and thus precise information can
be obtained with respect to the state of the food product under
treatment, the degree of preparation of the food product being
processed, the state of the oven muffle and the oven cavity
including any components therein. By evaluating the monitored
parameters, potentially detrimental or even hazardous situations
can be prevented, such as overheating of food or of oven
components. Apart from providing for prevention against abnormal or
abusive operation of the appliance, continuously monitoring
respective parameters also allows for automation of the food
treatment, wherein the appliance automatically adjusts operation
parameters in dependency of the monitored parameters.
[0008] Preferred embodiments of the present invention are defined
in the dependent claims.
[0009] Thus, in order to facilitate removal of heat from the
sensor, preferably a heatsink is disposed within the housing in
contact with the sensor. The heatsink preferably is an element
having a large thermal capacity, and further preferably is designed
to have a large surface area so as to facilitate heat exchange with
its surroundings, so that the heat sink acts as a dissipator for
the heat that has been captured.
[0010] To improve the heat transfer between the heatsink and the
sensor, preferably a thermal interface material is disposed between
the heatsink and the sensor, such as thermal grease, thermal glue
or a thermal adhesive, which improves the thermal conductivity
between the heatsink and the sensor by eliminating gaps or spaces
between these components.
[0011] The sensor can comprise any sensor, or combination of
sensors, suitable to detect signals characteristic for a parameter
to be monitored. In particular, the sensor may comprise at least
one of an optical sensor, an imaging system, a humidity sensor, a
temperature sensor, a gas sensor, a sound sensor, and a chemical
sensor, or the like. Thus various signals can be picked up to
monitor the cooking progress. Amongst optical parameters to be
monitored are to be named the amount and distribution of food items
loaded into the oven, a change in color of food items processed
such as the degree of browning of an article being roasted or
baked, a change in shape, such as the rising of a dough, and the
like. While temperature and humidity within the oven cavity are
important parameters to be monitored by respective sensors, sound
sensors can be employed for example for boiling detection, or for
detection of certain sound events such as the popping sound when
preparing popcorn. Vapor sensors, gas sensors or other chemical
sensors can be employed to detect the generation of various
substances.
[0012] In preferred embodiments, the housing comprises a cover
which covers a receptive region of the sensor element but which is
permeable for the physical or chemical parameter to be detected by
the sensor.
[0013] Thus, when the sensor is a humidity sensor, the cover
preferably comprises a membrane, such as a PTFE membrane, which is
permeable for water vapor, but which protects the receptive region
of the sensor from water and dust.
[0014] When the sensor is an optical sensor, the cover preferably
comprises a transparent element, such as a cover made of glass or
transparent plastic, wherein in further preferred embodiments the
transparent element is designed as an optical filter and/or lens,
so as to further enhance and optimize the optical transmission to
the sensor.
[0015] In order to avoid rapid warming of the sensor housing, the
housing or at least parts thereof are made from a material having a
thermal conductivity at standard conditions (i.e. atmospheric
pressure and a temperature of about 293 K) of less than 10 W/m*K,
preferable of less than 1 W/m*K, which can be realized for example
with certain heat resistant plastic materials, such as PTFE.
[0016] To provide for further variability in mounting the sensor
assembly to elements of an oven cavity, the assembly can comprise a
housing support for mounting the housing to a wall of the oven
cavity, which housing support can be designed not only to
facilitate mounting of the sensor assembly, but also to provide for
further thermal protection of the assembly, such as by making the
housing support of a material which has a lower thermal
conductivity than the housing.
[0017] The present invention further is an oven with an oven cavity
and an assembly as it is described above, wherein the oven
comprises means for generating a forced air flow which is directed
to the air inlet, and wherein the assembly is located within the
oven cavity. Due to the fact that the assembly comprises a housing
within which there is disposed the sensor and which is designed
such that an air flow can be passed through the housing so as to
cool the sensor, the assembly can be located within the oven cavity
as such where it can be used for direct measurements of parameters
to be monitored.
[0018] The air flow to be passed through the housing so as to cool
the sensor can be generated either by a fan that is used to feed
air into the oven cavity, wherein the air flow to the sensor
assembly is diverted from the air volume passed into the cavity. In
order to provide for cooling of the sensor assembly independent
from the operation of the fan that is used to provide air into the
oven cavity, preferably the oven is equipped with a dedicated fan
that is used to provide air for cooling one or more sensor
assemblies.
[0019] In a further embodiment, the present invention is an oven
with an oven cavity and an assembly as it is described above,
wherein the assembly is mounted to the exterior side of a wall of
the oven cavity and communicates with the interior of the oven
cavity through a region provided in the wall of the oven cavity
which is permeable for the physical or chemical parameter to be
detected by the sensor. Depending on the parameter to be detected,
such permeable region can be simply an opening in the wall of the
oven cavity, or a transparent element, a sound-transmissive
element, a light-transmissive element, a membrane, and the
like.
[0020] To reduce the number of parts, the housing can be formed in
part by a deep drawn region in a wall of the oven cavity.
[0021] The air which is passed into the assembly housing for
cooling of the sensor either can be expelled into the oven cavity,
or can be used for further purposes, such as for the cooling of at
least one further sensor assembly, for cooling an exterior wall of
the assembly housing, or can be vented to the exterior of the
oven.
[0022] Both, in embodiments in which the assembly is mounted to the
exterior side of a wall of the oven cavity and communicates with
the interior of the oven cavity through a permeable region in the
wall of the oven cavity, but also in embodiments in which the
assembly is mounted within the oven cavity and wherein the sensor
assembly as such comprises a permeable cover, the air outlet
advantageously comprises one or more outlet openings located in the
perimeter of the cover, so as to provide for an air stream which
protects the permeable region or the cover, respectively, from oven
fumes, so as to prevent soiling for example by oil or soot
particles contained in such fumes.
[0023] To further improve such protecting effect of the exiting air
flow, the outlet openings are arranged such that the air is
expelled in a turbulent flow, as may be attained for example by
merging the exit flows leaving individual outlet openings, such as
by providing for an inclination of the axis along which the air
flows leave the outlet openings, or by orienting the outlet
openings in a manner so as to provide for a swirling flow.
[0024] To further prevent heating of the assembly, an insulation
layer can be provided at a wall of the housing which faces towards
the oven cavity.
[0025] In embodiments of the present invention, elements of the
assembly can be formed as an integral part so as to facilitate
mounting of the assembly by reducing the number of elements to be
assembled. Thus, for example a heat sink can be formed as an
integral part of the housing.
[0026] Preferred embodiments of the present invention will be
described by reference to the drawings in which:
[0027] FIG. 1 shows a sectional view of a first embodiment of a
sensor assembly in accordance with the present invention;
[0028] FIG. 2 shows a sectional view of a second embodiment of a
sensor assembly in accordance with the present invention;
[0029] FIG. 3 shows a sectional view of a third embodiment of a
sensor assembly in accordance with the present invention;
[0030] FIG. 4 is a perspective view of the sensor assembly
illustrated in FIG. 2;
[0031] FIG. 5 illustrates an exploded view of a sensor assembly in
accordance with the present invention, wherein the sensor is an
optical sensor; and
[0032] FIG. 6 illustrates an exploded view of a sensor assembly in
accordance with the present invention, wherein the sensor is a
humidity sensor.
[0033] FIG. 1 illustrates a sensor assembly made in accordance with
the present invention. Sensor assembly 10 comprises a housing 12 in
which there is located a sensor element 14, which in the embodiment
shown in FIG. 1 comprises an imaging system having a camera.
Housing 12 comprises an air inlet 16 for feeding air into the
housing 12 and an air outlet 18 through which air can leave the
housing 12 upon having passed over and along the sensor element 14
for cooling thereof, as is depicted in FIG. 1 by arrows. To further
facilitate heat being withdrawn from sensor element 14, the sensor
assembly 10 comprises a heat sink 20 which is mounted on the side
of the sensor element 14 facing away from an oven cavity 22, which
is formed by an oven muffle of which in FIG. 1 there only is shown
a portion of an upper wall 24.
[0034] As shown in FIG. 1, sensor assembly 10 comprises an annular
portion 26 protruding from a bottom wall 28 of housing 12, which is
mounted within an opening 30 of the upper wall 24 of the oven
muffle. To prevent oven fumes from entering the annular portion 26,
there is provided a transparent element 32 which enables the sensor
element 14 to monitor the interior of the oven cavity 22.
[0035] FIG. 2 shows a sensor assembly which differs from the one
illustrated in FIG. 1 in that the air that is passed into the
housing 12 via air inlet 16 is expelled into the oven cavity 22. To
this end housing 12 comprises a wall 34 that closes the end of the
housing 12 opposite air inlet 16, and further comprises an air
outlet 36 at the bottom of annular portion 26. As is shown in
further detail in the perspective view of FIG. 4, annular portion
26 can be designed as an annular channel, into which air leaving
housing 12 enters via a plurality of openings 37 and from which the
air is passed into the oven cavity 22 in an annular flow around
transparent element 32 via a plurality of outlet openings 38.
[0036] In the embodiment illustrated in FIGS. 2 and 4, the sensor
assembly 10 further is designed for use in an oven that in addition
to a heating capability, such as by heating elements, hot air or
steam, further provides for a microwave function. While the sensor
assembly 10 is protected from oven fumes by the transparent element
32, in order to protect the sensor element 14 from microwaves there
additionally is provided a metallic wall 39 having an aperture 40
in close proximity to the optical sensor element 14.
[0037] As can be best seen in FIG. 4, the heat sink 20 is provided
with a plurality of fins 42 which provide for a large surface area
of the heat sink 20 to thus improve the heat exchange with cooling
air that is passed through the housing 12.
[0038] In FIG. 3 there is shown a variant of a sensor assembly 10
that is similar to the ones shown in FIGS. 1 and 2, but in which
the air leaving housing 12 is expelled laterally from the annular
portion 26, so as to be fed into the space between upper wall 24 of
the oven muffle and bottom wall 28 of housing 12, so as to provide
for additional cooling of housing 12 and further to provide for an
insulating air layer between the upper wall 24 of the oven muffle
and the bottom wall 28 of the assembly housing 12.
[0039] While in the embodiments shown in FIGS. 1 and 3 the air flow
after cooling the sensor is used to provide for further cooling,
either of another sensor as in the FIG. 1 embodiment, or another
part of the same sensor assembly as in the FIG. 3 embodiment, the
air leaving the sensor assembly also can be used to provide a
dynamic air barrier, preferably by providing for a turbulent
swirling flow, which prevents oven fumes or other dirt particles
from reaching the active sensor area.
[0040] Whereas in the embodiments illustrated in FIGS. 1 to 4 at
least a portion of the sensor assembly 10 is located behind a wall
of the oven muffle, it is to be understood that similarly as is
shown for the annular portion 26, also the entire bottom wall 28
could be in direct contact with the interior of the oven cavity 22,
such as by arranging assembly 10 in an opening in a wall of the
oven muffle (similarly as opening 30), the size of which
corresponds to the size of the bottom wall 28. Furthermore, due to
the cooling capacity of the sensor assembly also the entire sensor
assembly 10 could be arranged within the interior 22 of the oven
cavity, such as within a depression of a wall of the oven muffle,
which depression may be formed as a deep drawn region of the oven
muffle.
[0041] The sensor assembly suggested herein is capable of
sufficiently cooling sensors for use within a baking oven, which
further to having resistance heating elements may incorporate at
least one other heating technology, such as steam generation or
microwave generation, and which further may be provided with a
pyrolytic cleaning capacity.
[0042] In FIG. 5 there is shown an exploded view of a further
embodiment of a sensor assembly 10 in accordance with the present
invention.
[0043] The sensor assembly 10 shown in FIG. 5 comprises a generally
box shaped housing 12 which at one end comprises an integrally
formed air inlet 16. Housing 12 which is open at its upper side
comprises a bottom wall 28 in which there are provided a plurality
of outlet openings 43 which are located to form a circle around a
central opening 44. Within housing 12 there is located a sensor
element 14, which in the embodiment depicted in Fig, 5 is designed
as an optical sensor having a camera element 46 which in the
assembled state is located above central opening 44. Above sensor
element 14 there is shown a heat sink 20 which in the assembled
state contacts sensor element 14 so as to withdraw heat from the
sensor element. Similarly as the heat sink 20 shown in FIG. 4, also
in the embodiment shown in FIG. 5 the heat sink 20 comprises a
plurality of lamellas 42 so as to increase the surface area of heat
sink 20 about a channel 48 through which air is passed during use
of the sensor assembly. The opening at the upper side of housing 12
is closed by a lid 50, which further also could be formed as an
integral part with the heat sink 20.
[0044] While so far the sensor assembly 10 shown in FIG. 5 is
similar to the one shown in FIGS. 2 and 4, in the FIG. 5 embodiment
there is provided a housing support 52 for mounting the sensor
assembly to a wall of the oven cavity, either at the exterior side
or at the interior side thereof. The housing support 52 is made of
a temperature resistant material which preferably has a lower
thermal conductivity than the housing 12 so as to provide for
thermal protection thereof. Housing support 52 comprises at its
upper side an annular wall 54 within which there is provided a
receptacle (not shown in FIG. 5) for a transparent element 32, and
which forms together with an annular element 56 an annular channel
for air leaving outlet openings 28. Housing support 52 further
comprises supports 58 and 60 for supporting the bottom wall 28 of
housing 12. In order to provide for additional thermal insulation
of housing 12, an insulation layer 62 is provided at the bottom
wall 18 of housing 12.
[0045] In FIG. 6 there is shown a sensor assembly similar as the
one shown in FIG. 5, wherein the assembly comprises a housing 12
that is mounted on a housing support 52. However, in the embodiment
shown in FIG. 6, the assembly is designed for use with a humidity
sensor 64. Furthermore, in contrast to the embodiment shown in FIG.
5, where the air used for cooling the sensor is expelled into the
oven cavity, in the embodiment shown in FIG. 6 there is provided an
air outlet 18 as is shown also in FIG. 1.
[0046] Correspondingly the bottom wall 18 of housing 12 has no air
opening 28 as shown in FIG. 5, but only is provided with an opening
44 that is in alignment with the humidity sensor 64 as shown in
FIG. 6. In order to protect humidity sensor 64 from contact with
water droplets or other particles contained in the oven fumes,
there is provided an annular element 66 which carries a membrane 68
that is permeable to water vapor. Element 70 shown in FIG. 6 is a
connection ring for mounting humidity sensor 64 within housing
12.
REFERENCE SIGNS
[0047] 10 sensor assembly
[0048] 12 housing
[0049] 14 sensor element
[0050] 16 air inlet
[0051] 18 air outlet
[0052] 20 heat sink
[0053] 22 oven cavity
[0054] 24 upper wall of oven muffle
[0055] 26 annular portion
[0056] 28 bottom wall of 12
[0057] 30 opening in 24
[0058] 32 transparent element
[0059] 34 wall of 12
[0060] 16 air outlet
[0061] 37 openings
[0062] 38 outlet openings
[0063] 39 metallic wall
[0064] 40 aperture
[0065] 42 fins
[0066] 43 outlet openings
[0067] 44 central opening
[0068] 46 camera element
[0069] 48 channel
[0070] 50 lid
[0071] 52 housing support
[0072] 54 annular wall
[0073] 56 annular element
[0074] 58 support
[0075] 60 support
[0076] 62 insulation layer
[0077] 64 humidity sensor
[0078] 66 annular element
[0079] 68 membrane
[0080] 70 connection ring
* * * * *